Search found 4861 matches

by Jirka
Fri Mar 27, 2020 2:53 pm
Forum: Hydrus 1D
Topic: HYDRUS 1D Model Fails to Converge
Replies: 17
Views: 11454

Re: HYDRUS 1D Model Fails to Converge

From your input I can see that you use either the Kosugi (Model=3) or Durner dual-porosity (Model=5) models. Durner model is obviously not based on the Kosugi's model, but on the van Genuchten-Mualem model. Thus, if you want to compare these two simulations, you need to use consistent models.

J.
by Jirka
Wed Mar 25, 2020 4:24 pm
Forum: Hydrus 1D
Topic: HYDRUS 1D Model Fails to Converge
Replies: 17
Views: 11454

Re: HYDRUS 1D Model Fails to Converge

It very likely will. Why wouldn't you simply test it yourself? J.
by Jirka
Sun Mar 15, 2020 5:50 pm
Forum: HP1 (HYDRUS-1D - PHREEQC)
Topic: how to setup correct ph for soultions
Replies: 2
Views: 1037

Re: how to setup correct ph for soultions

You need to use the keyword "charge", which will indicate the code, which species to adjust to get charge balance. J. SOLUTION 1 pH 7 charge Cl 0.01 Na 1 SOLUTION 2 Cl 1.3 charge Na 2 In the first example, pH of this solution will be adapted to obtain charge balance => pH = 10.98. In the second exam...
by Jirka
Sat Mar 14, 2020 2:58 pm
Forum: HYDRUS (2D/3D)
Topic: Water and solute mass balance error
Replies: 2
Views: 979

Re: Water and solute mass balance error

I think that these are acceptable mass balance errors. I usually want from the simulation to have the mass balance error for water flow less than 1% (which you have almost 10 times smaller) and for solute transport less than 2-3% (which you also have). You can likely lower the mass balance errors ev...
by Jirka
Wed Mar 11, 2020 9:05 pm
Forum: Hydrus 1D
Topic: BEGINNER: HELP WITH LEARNING HYDRUS 1D
Replies: 2
Views: 482

Re: BEGINNER: HELP WITH LEARNING HYDRUS 1D

The best way to learn HYDRUS-1D is with the CSIRO Tutorial eBook: Rassam, D., J. Šimůnek, D. Mallants, and M. Th. van Genuchten, The HYDRUS-1D Software Package for Simulating the Movement of Water, Heat, and Multiple Solutes in Variably Saturated Media: Tutorial, Version 1.00, CSIRO Land and Water, ...
by Jirka
Wed Mar 11, 2020 5:33 pm
Forum: HYDRUS (2D/3D)
Topic: Export of the seepage line / phreatic line
Replies: 3
Views: 546

Re: Export of the seepage line / phreatic line

There is an easy way to export x-z coordinates of isolines. 1. First, you need to switch the View to display Isolines: Options->Scalar Field Display->Isolines 2. Then, you use the command Export Isolines (File->Export->Export Isolines). The program than creates a text file "Project_Name_Isolines.txt...
by Jirka
Tue Mar 10, 2020 9:52 pm
Forum: Hydrus 1D
Topic: Confined Aquifer/Positive Lower Boundary Head
Replies: 3
Views: 659

Re: Confined Aquifer/Positive Lower Boundary Head

Let me quote from the help: "Free Drainage Water Flow Boundary Condition: A zero-gradient boundary condition can be used to simulate a freely draining soil profile. Such a situation often occurs in field studies of water flow and drainage in the vadose zone. This lower boundary condition is most app...
by Jirka
Tue Mar 10, 2020 8:50 pm
Forum: Hydrus 1D
Topic: Confined Aquifer/Positive Lower Boundary Head
Replies: 3
Views: 659

Re: Confined Aquifer/Positive Lower Boundary Head

The pressure head BC, with the pressure head at the bottom of the domain. J.
by Jirka
Mon Mar 09, 2020 9:36 pm
Forum: HYDRUS (2D/3D)
Topic: error during mesh generation
Replies: 13
Views: 5330

Re: error during mesh generation

I would not care that much about streamlines (and velocities) since that is simply postprocessing of results by GUI. I would care more about the calculated pressure heads and boundary fluxes, which are a direct result of calculations. J.
by Jirka
Wed Mar 04, 2020 6:30 pm
Forum: HYDRUS (2D/3D)
Topic: error during mesh generation
Replies: 13
Views: 5330

Re: error during mesh generation

As I wrote above you need to test different grids, with such a large grid anisotropy. You should look at the mass balance errors and accept results that gives you good mass balance errors. J.
by Jirka
Mon Mar 02, 2020 5:29 pm
Forum: HYDRUS (2D/3D)
Topic: error during mesh generation
Replies: 13
Views: 5330

Re: error during mesh generation

Since the pressure head isolines in your problem are likely horizontal, you should use an anisotropic FE mesh. For such conditions you can easily use an anisotropy ratio of the mesh of 1:10, 1:100, or even more. You need to test it. Also, note that you need to have finer discretization only in the u...
by Jirka
Wed Feb 26, 2020 5:33 pm
Forum: Hydrus 1D
Topic: Storage of probe
Replies: 3
Views: 770

Re: Storage of probe

HYDRUS provides a graph of Soil Water Storage for the entire profile, as well as Soil Water Storage for different Subregions at Print Times in the Mass Balance Information output. J.
by Jirka
Tue Feb 25, 2020 5:27 pm
Forum: Hydrus 1D
Topic: Storage of probe
Replies: 3
Views: 770

Re: Storage of probe

All reported values by HYDRUS related to water content and water storage are in volumetric units, i.e., [cm^3/cm^3] or [cm]. J.
by Jirka
Mon Feb 24, 2020 2:19 am
Forum: HYDRUS (2D/3D)
Topic: Handling water balance error in wet conditions
Replies: 12
Views: 1334

Re: Handling water balance error in wet conditions

I have found out where the problem was. If I decrease the precision criteria used in the matrix solver (ORTHOMIN), I will avoid these mass balance error problems. Please download the attached computational modules and copy them into the BIN folder, in which HYDRUS is installed (e.g., …. HYDRUS3D 3.0...
by Jirka
Fri Feb 21, 2020 9:07 pm
Forum: Hydrus 1D
Topic: Error in time steps
Replies: 7
Views: 635

Re: Error in time steps

You likely have problems exactly because you changed the default parameters. The minimum allowed time step clearly should be smaller or equal to the initial time step, and it should be on the order of 1 s, certainly not 0.5 days. Specifying any value other than zero for the bottom flux is almost alw...